Nobody can accurately predict what they will do. They are living animals, each with their own personality. There is a current thread where a lady put young chicks under a hen that had only been broody a couple of days and it looks like she accepted them. That one could have easily gone another way. I wait at least two days to give any broody eggs just to make sure she is serious about being broody.
I don't know how valuable those eggs are to you. There is a risk involved any time a broody is involved, but there are also risks in an incubator. I don't think chickens can count days all that well but I'm also not sure how those hormones that control being broody really work.
I'd probably risk it with my eggs, but I hatch my own and can always put a few in the incubator if I need more chickens. And I really like having a broody raise them. I think there is a fairly good chance she will hear them in the eggs as they prepare to hatch and that will get her in the right mood, but there is always a risk. I think your risks are less than the lady that got a new broody to accept young chicks since she will actually hatch them herself, but that depends on the personality of your individual hen.
Good luck!
